<!DOCTYPE html>
<html>
  <head>
    <style>
      table {
        width: 300px;
        height: 300px;
        background-color: blue;
      }
      td, div {
        margin: 0;
        padding: 0;
      }
      #rel {
        position: relative;
        margin: 0;
        padding: 0;
        height: 1px;
      }
      #abs {
        position: absolute;
        margin: 0;
        padding: 0;
        top: 200.5px;
        left: 25px;
        width: 50px;
        height: 50px;
        background-color: green;
      }
    </style>
  </head>
  <body>
    The green square should not touch the blue square.
    <table>
      <colgroup>
        <col style="width: 15%">
        <col>
      </colgroup>
      <tr>
        <td></td>
        <td></td>
      </tr>
      <tr>
        <td>
          <div id="rel">
            <div id="abs"></div>
          </div>
        </td>
        <td></td>
      </tr>
    </table>
  </body>
</html>
